On Sun, 20 Jan 2002, Roman Black wrote:

>
> >   I'm agree with you here... except that all serious
> > laser driver hasn't a simple resistor for constant
> > current but a specialised chip soldered very close to
> > the laser. That's because of high current treshold
> > ( greater than 7Amps ) needed to lasser effect begun.
> > I'm talking now about high power lasser diode which are
> > not working in CW, but also about 3mW CW laser diode
> > from CD-rom drive, both have a specialised circuit.
>
> I don't understand this, i've driven 5mW red lasers
> fine with a 100mA constant current supply. You are saying
> they need 7A to start? Is that to get them turned on
> quickly enough, ie effects of the internal R and C
> of the laser?

  Oh my damn english !
  Small power CW lasers are working ok with your solution.\
  High power pulsed lasers have a thresold of about 7 to 10
  amperes ( even if an IR 10W laser diode looks exectly like
  an ordinary 5mm led ) and need specialised driving IC/circuit, else
  the laser effect will not take place ( at less then current thresold
  will work like an ordinary IR led )

Vasile

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